A new study offers up a simple solution to stop corrosion at the source.

Thank goodness for sewers. They protect us from waterborne diseases and putrid smells, allowing us to live in dense, bustling cities.

Now we can return the favor and keep them safe: According to research published today in the journal Science governments can reduce corrosion by making a simple switch in the chemicals that clean drinking water.

Typically, sewers last anywhere between 50 and 100 years; however, depending on the quality of construction, sewage, and other factors, pipes can collapse in only 10 or 20 years and cost billions to replace.

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Most corrosion happens when bacteria transform sulfate in the wastewater to corrosive sulfuric acid. Three sources contribute to higher sulfate levels: aluminum sulfate additives that purify water, human waste, and natural water sources such as reservoirs.

The researchers wanted to discover how much sulfate each source contributed. So they surveyed drinking water and wastewater facilities across Australia, taking water samples. They found that 50 percent of the sulfate came from the water treatment additives.

Using a simulation that modeled corrosion in sewer pipes, the scientists found they could reduce decay by 60 percent by replacing the aluminum sulfate with sulfate-free chemicals. Some utilities already use sulfate-free additives to treat water, so the switch could be a lower-cost solution than fixing broken pipes. Additionally, water treatment plants could even remove sulfate from natural sources by desalination.